Dr. AIX's POSTS HD-AUDIO — 15 June 2018


I admit to spending too much time cruising FB. And too many of my FB friends and groups are audio related. When I see a post or comment that tweaks my sensibility, I am not shy about posting a comment or linking to a counter argument. During one such discussion yesterday, I made my usual statement that virtually ALL content available on so called “high-resolution” download sites doesn’t qualify as high-resolution — at least in my stringent definition. I’ve downloaded and analyzed dozens of albums from a variety of sites (Qobuz, HDtracks, ProStudioMasters etc.), Some of them were older and obviously from analog masters (Cat Stevens “Tea for the Tillerman” and Neil Young’s “Harvest”) while others are newer and produced using digital tools (James Taylor’s “Before This World” and Kacey Musgraves’ “Golden Hour”, which includes her hit “Slow Burn”). And while these albums sound very good — probably the best we’ll ever get — they are produced and engineered to meet the demands of the commercial marketplace. They are mastered to sound loud on the radio, ear buds, smartphones, Bluetooth speakers, downloads, and CDs.

The proprietor of a European high-resolution download site (and just announced “high-res” streaming) has posted some comments that push back on my position. He claims that the files available on his website are “Native 24bit FLAC at sampling rates up to 192kHz. Fully tested verified and analyzed files. No up-sampled, technically manipulated, tweaked or re-encoded treatment!!” However, a review of the album by Paul Miller in his magazine HiFi News reports, “The download may light the 96kHz LED on your DAC, and appear as ’96kHz’ on your PC/Mac music software, but spectral evidence suggests it’s largely upsampled from 44.1kHz (CD) with aliasing distortion above 20kHz.” As you would expect, the online exchange continued with additional evidence and arguments.

Then the founder of the online service revealed something that I hadn’t heard previously. He commented, “This album is strategic release from the record company and we can not deny the release! Sometimes it is difficult to evaluate the situation. Strategic release we have to put online!” Wow! I interpreted this to mean that the licensing agreement he has with MCA Nashville — or the parent company MCA Universal — mandates that the site offer this “strategic album” regardless of whether it qualifies as a true high-resolution album or not. All of the voodoo “tested and verified” stuff at this site and others goes out the window if they “have to put (it) online.” How are consumers supposed to know what is and isn’t a “strategic release”?

Additional comments had the founder posting an analysis of the “Slow Burn” track (and others) to refute the assertions made in HiFi News. Here’s his posted image from the program Sound Mirror:

This is the track “Slow Burn” by Kacey Musgraves as provided by the high-res download site. [Click to enlarge]

I find it odd that the “text balloon” is strategically placed right at point where the spectral line dips. And the obvious purple vertical line at around 40 kHz ISN’T reflected in the plot line to the right of the “text balloon” as expected. Was this plot altered or just the result of a poor tool?

Here’s the analysis that Paul Miller provided in his publication HiFi News:

Notice the steep drop just above 20 kHz. [Click to Enlarge]

Curious how the two plots don’t match — they should. The steep drop at just above 20 kHz — like an upconversion would show — is obvious in the HiFi News plot. Another aspect of Paul’s spectra is the flat line from 48 kHz to 96 kHz. The file he analyzed has a sample rate of 192 kHz. However there is no audio information above 48 kHz and no musical information above 24 kHz. Why would anyone feel better about this 192 kHz file over the original 48 kHz version? Consumers are being asked to pay for empty data or just noise.

I wanted to do the analysis of the same track myself so I downloaded the same album from HDtracks (I actually became a fan of Kacey after seeing her on SNL) and ran “Slow Burn” through my preferred analysis tool Adobe Audition. Here’s the information I extracted:

The “Slow Burn” track showing the spectral balance in the lower left hand corner, the linear plot of amplitude vs. frequency in the upper right, and the dynamic range of the tune in the lower right. [Click to Enlarge]

My analysis closely matches the one from HiFi News except the sample rate of my download is 96 kHz not 192 kHz. I annotated the various sections of the Audition page to highlight some area of interest. The amount of ultrasonic information is very light and doesn’t appear to be music partials. The steep drop at 24 kHz means that the original was captured at 48 kHz (Nyquist of 24 kHz) and the abrupt spike at 40 kHz is most likely the bias frequency of an analog tape machine — or it could be some other artifact (I’ve seen automation systems create similar intrusions). Most notable — and something that is not addressed in the first Sound Mirror image — is the very narrow dynamic range of this tune. It’s not at all surprising that the mastering stage of a contemporary country/pop tune has been heavily compressed. Having 24-bit containers with a mere 5-6 bits of dynamic range is quite common. The -10.13 LUFS means that this track doesn’t use the full potential of 24-bits (however, most releases follow this model).

So who are we to believe? The proprietor of a so called “high-res” download and streaming service or Paul Miller from HiFi News? My investigation confirmed Paul’s analysis AND affirms my position that virtually ALL high-resolution music offered as streams, MQA, or downloads is not high-resolution. It doesn’t seem to matter whether the content is 50 years old or recorded more recently. The engineers that I know and speak with are still recording at 48 kHz/24-bits. There’s very little incentive or benefit to go any higher knowing that the final master will have less fidelity than a CD.

Should we abandon high-resolution downloads or streaming? If you have the money and feel better getting a big bit bucket full of the same fidelity we get from the original or vinyl LP, then keep spending your money on expensive “high-res” audio. I gave up that pursuit long ago.


PS Many readers have written and asked for the credentials to the FTP site so they can participate in the High-Res Challenge. Be patient. The server can only accommodate 7 people at a time. If you get locked out, try again later. I will be putting a new page on this site to collect responses. Stay tuned.

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About Author


Mark Waldrep, aka Dr. AIX, has been producing and engineering music for over 40 years. He learned electronics as a teenager from his HAM radio father while learning to play the guitar. Mark received the first doctorate in music composition from UCLA in 1986 for a "binaural" electronic music composition. Other advanced degrees include an MS in computer science, an MFA/MA in music, BM in music and a BA in art. As an engineer and producer, Mark has worked on projects for the Rolling Stones, 311, Tool, KISS, Blink 182, Blues Traveler, Britney Spears, the San Francisco Symphony, The Dover Quartet, Willie Nelson, Paul Williams, The Allman Brothers, Bad Company and many more. Dr. Waldrep has been an innovator when it comes to multimedia and music. He created the first enhanced CDs in the 90s, the first DVD-Videos released in the U.S., the first web-connected DVD, the first DVD-Audio title, the first music Blu-ray disc and the first 3D Music Album. Additionally, he launched the first High Definition Music Download site in 2007 called iTrax.com. A frequency speaker at audio events, author of numerous articles, Dr. Waldrep is currently writing a book on the production and reproduction of high-end music called, "High-End Audio: A Practical Guide to Production and Playback". The book should be completed in the fall of 2013.

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